As soon as the repugnant photos of torture at Abu Ghraib prison -- the pyramid of naked prisoners, the groveling man on a dog leash, the hooded man with outstretched arms -- hit the airwaves and newspaper stands, they became iconic images: gruesome symbols of what went wrong with the war and postwar occupation of Iraq, and for many in the Muslim world, the very embodiment of their worst fears about American hegemony.

They have become a potent propaganda tool for terrorists, and at the same time, they remain so repellant and perverse that they have served to bolster the "few bad apples" argument -- the suggestion not only that the photographed abuses were perpetrated by "a kind of 'Animal House' on the night shift," in one investigator's words, but also that the larger problem was confined, as the Bush administration has asserted, to a few soldiers acting on their own.

"The Torture Papers," the new compendium of government memos and reports chronicling the road to Abu Ghraib and its aftermath, definitively blows such arguments to pieces. In fact, the book provides a damning paper trail that reveals, in uninflected bureaucratic prose, the roots that those terrible images had in decisions made at the highest levels of the Bush administration -- decisions that started the torture snowball rolling down the slippery slope of precedent by asserting that the United States need not abide by the Geneva Conventions in its war on terror.

Many of the documents here have been published before (most notably in Mark Danner's incisive 2004 volume "Torture and Truth"), but "The Torture Papers" contains some material not collected in earlier books. More important, the minutely detailed chronological narrative embodied in this volume, which has appeared piecemeal in other publications, possesses an awful and powerful cumulative weight. As one of its editors. Karen J. Greenberg, executive director of the Center on Law and Security at the New York University School of Law, observes, it leaves the reader with "a clear sense of the systematic decision to alter the use of methods of coercion and torture that lay outside of accepted and legal norms."

The book is necessary, if grueling, reading for anyone interested in understanding the back story to those terrible photos from Saddam Hussein's former prison, and abuses at other American detention facilities.

As this book makes clear, one of the premises that would inform many of the administration's decisions was an amped-up view of executive power -- the notion, as Deputy Assistant Attorney General John C. Yoo put it shortly after 9/11 -- that "the power of the president is at its zenith under the Constitution when the President is directing military operations of the armed forces," and that he has the authority "to take whatever actions he deems appropriate to pre-empt or respond to terrorist threats from new quarters" whether or not such entities can be "demonstrably linked to the September 11 incidents." Indeed, Justice Department memos suggested that in a war like the present one, presidential power can override both congressional laws and "customary international law": in short, that the president can choose to suspend America's obligation to comply with the Geneva Conventions if he wishes, authorize torture or detain prisoners without a hearing.

On Feb. 7, 2002, President Bush signed an order that would have all manner of unreckoned consequences: "I accept the legal conclusion of the Department of Justice and determine that none of the provisions of Geneva apply to our conflict with al Qaeda in Afghanistan or elsewhere throughout the world." Instead, prisoners at Guantánamo Bay were to be designated "unlawful combatants," who fell under rules that the administration itself would determine. That included all Qaeda suspects and Taliban detainees, who President Bush said were not entitled to prisoner of war status, but should instead be treated "humanely and, to the extent appropriate and consistent with military necessity, in a manner consistent with the principles of Geneva." In September 2002, a secret C.I.A. study raised questions about the significance of the Guantánamo detainees, reportedly suggesting that many of them might be low-level recruits or even innocents swept up in the fog of war.

Secretary of Defense Donald H. Rumsfeld would later approve the use of special interrogation techniques for key terrorist suspects. Eventually techniques designed to be used on hard-core al Qaeda suspects at Guantánamo migrated to Iraq, where military intelligence officers told the Red Cross an estimated 70 percent to 90 percent of the detainees had been arrested by mistake.

A second seminal premise embraced by the administration was that the global war on terrorism represents "a new paradigm," and that this new sort of war required new sorts of tools. In an interview on Sept. 16, 2001, Vice President Dick Cheney reworked the means-and-ends equation, asserting that the United States was going to have to work "sort of the dark side" and that "it's going to be vital for us to use any means at our disposal, basically, to achieve our objective." Alberto R. Gonzales, the White House counsel at the time, was more specific; he argued that the "new paradigm renders obsolete Geneva's strict limitations on questioning of enemy prisoners."

There were some dissenting voices. In January 2002, Secretary of State Colin L. Powell argued that withholding prisoner of war status across the board (instead of case by case) to al Qaeda and Taliban suspects would "reverse over a century of U.S. policy and practice," "undermine the protections of the law of war for our troops," have "a high cost in terms of negative international reaction" and "undermine public support among critical allies." His warnings were not heeded.

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Instead, more and more attention was focused on articulating a narrow definition of torture and proposing strategies to avoid prosecution of American interrogators. Justice Department and Defense Department memos on this subject make for chilling reading, and they transport the reader from the sunlit world of "democracy" and "freedom" and "human rights" frequently invoked by the president to a dark place located somewhere in the nether latitudes between Orwell's "Animal Farm," the "Godfather" movies and one of Joseph Heller's or Kurt Vonnegut's black comedies.

Here, lawyerly language is used to draw excruciatingly fine distinctions between "torture" and "cruel, inhuman, or degrading treatment." Bureaucratic charts are drawn up, detailing 35 types of interrogation techniques, their "utility" and their ranking vis-à-vis various torture conventions and American domestic law. And exacting efforts are made to define torture in the very narrowest of terms: in an August 2002 memo, Assistant Attorney General Jay S. Bybee wrote that a victim must experience the sort of pain and suffering "associated with serious physical injury so severe that death, organ failure, or permanent damage resulting in a loss of significant body function will likely result."

There are discussions about "the lowest boundary of what constitutes torture," a "risk benefit analysis" of interrogation techniques and references to "exceptional techniques" -- phrases reminiscent of the sort of language used during the Vietnam War, like "eliminating assets," "interdictional nonsuccumbers" and "effective delivery of ordnance."

In addition to such semantic manipulation and parsing of the law, government lawyers struggled to come up with possible defense strategies. In a 2002 memo, Mr. Bybee wrote: "Certain justification defenses might be available that would potentially eliminate criminal liability. Standard criminal law defenses of necessity and self-defense could justify interrogation methods needed to elicit information to prevent a direct and imminent threat to the United States and its citizens."

A 2003 Pentagon working group report on detainee interrogations suggested that "lawfulness will depend in significant part on procedural protections that demonstrate a legitimate purpose and that there was no intent to inflict significant mental or physical pain."

Not surprisingly, the official investigations into the Abu Ghraib scandal provide a decidedly less panoramic view of the overall situation than this book does as a whole. As Mr. Danner has pointed out, the investigations tended to focus on particular aspects of the scandal -- the Taguba Report on the military police, the Fay-Jones Report on military intelligence, for instance -- and they also exhibit a reluctance to connect all the dots and explicate the implications of their findings.

For instance, the Schlesinger Report on Pentagon detention operations concluded that "abuses of varying severity" were "widespread." "There is both institutional and personal responsibility at higher levels," the report went on, noting that a lack of resources and failures in postwar planning helped create serious shortages in "manning levels" and a resulting atmosphere of confusion at Abu Ghraib. Direct responsibility, however, is focused on men and women on the ground: some incidents of abuse are attributed to "individual criminal misconduct;" others to "misinterpretations of law or policy or confusion about what interrogation techniques were permitted."

Only vague aspersions are cast on the Pentagon's civilian leadership. The report chirpily concludes that "while any abuse is too much, we see signs that the Department of Defense is now on the path to dealing with the personal and professional failures and remedying the underlying causes of these abuses."

What happened to higher-up architects and consultants on administration policy? Mr. Rumsfeld revealed last week that he twice offered to resign over the Abu Ghraib scandal and was twice turned down by President Bush. Mr. Bybee, who defined torture as pain equivalent to "organ failure," was nominated by Mr. Bush to the Ninth Circuit Court of Appeals and took his seat there in 2003. Michael Chertoff, who in his capacity as head of the Justice Department's criminal division advised the C.I.A. on the legality of coercive interrogation methods, was selected by President Bush to be the new secretary of homeland security. William J. Haynes II, the Department of Defense's chief legal officer, who helped oversee Pentagon studies on the interrogation of detainees, was twice nominated by President Bush to the Fourth Circuit Court of Appeals. And Mr. Gonzales, who used the words "obsolete" and "quaint" in reference to the Geneva Conventions, was confirmed last week as attorney general, the nation's top legal post.